A disposable diaper typically has a thin, flexible, low density polyethylene backing film or nonwoven film laminate, an absorbent core on the inside of the backing film, and a porous top sheet overlaying the core. The two ends of the diaper typically extend toward the front and the back around the user's waist. A closure system is typically positioned adjacent to the edges of the diaper. The closure system is typically a strip or tab of pressure sensitive adhesive tape or a mechanical fastener for holding the diaper to the wearer. Various finger grip configurations for adhesive based fasteners are disclosed in U.S. Pat. Nos. 3,893,460 (Karami); 3,937,221 (Tritsch); 4,043,340 (Cepuritis); 4,084,592 (Tritsch); 5,288,546 (Roessler et al.); and 5,399,219 (Roessler et al.).
Mechanical fasteners have the advantage that they may be repeatedly used for opening and refastening the disposable garment, while being less susceptible to contamination by oils, powders or debris which might interfere with the adhesion of an adhesive fastening tape tab. Various finger grip arrangements may be formed in the mechanical fastener to facilitate opening and refastening the disposable article.
U.S. Pat. No. 5,176,670 (Roessler et al.) discloses a diaper with two ear sections at the rear waistband portion having tape or hook tabs for fastening about the body of the wearer. The free end portion of the tape tab may optionally be folded upon itself to provide a grip portion at the distal end.
U.S. Pat. No. 5,053,028 (Zoia et al.) discloses a unitary polymeric hook fastener portion for use on a disposable garment having a plurality of hook members projecting from a backing. A minor portion of the backing projects from one side of the hook members and is positioned to be manually grasped to facilitate pealing the tab assembly.
U.S. Pat. No. 5,304,162 (Kuen) discloses a garment with a pleated adjustable strap member. A hook patch is positioned such that it extends past the ends of the pleated materials and the elastic material. The hook patch may include a free end that is rounded and void of hooks.
EP 0 563 458 discloses an adhesive/mechanical fastening system for a disposable absorbent articles with gripping tabs. The gripping tab is formed by folding the laterally outward edge of the user's region back onto itself and over part of the mechanical fastener member.
WO 95/05140 discloses a method of manufacturing mechanical fastening tapes for use on disposable garments. An interlocking material is attached to a substrate. The interlocking material is spaced from the second edge of the substrate to form a finger tab.
WO 96/21413 discloses a composite-prelaminated closure tape system having a mechanical fastener component bonded to a supporting sheet. The mechanical fastener may be configured with a free end without mechanical fasteners disposed thereon.
Canadian Patent Application No. 2,087,990 discloses a method and apparatus for forming selvages on a surface of a separable fastener. Press rolls press the separable fastener against an ultrasonic horn to fuse or weld the heated fastening elements into the substrate. The flat parts on the separable fastener form the selvages later in the process. The roll width of the press rolls is nearly the same as the width of the flat parts to be formed, and the pitch of the press rolls is the same as the pitch of the flat part. The clearance between the press rolls and the ultrasonic horn is adjusted to assure good fusing of the fastening elements with the substrate, thereby providing flat parts having a good, smooth surface. The press rolls and ultrasonic horn represent additional equipment for performing a separate manufacturing step that adds cost and delays the manufacturing of high volume fasteners.
Disposable articles, such as disposable diapers, must be made at a high rate of speed in order to be economical. It is thus desirable for a manufacturer of diapers to mount a single roll of closure tape in the form of an assembly containing all the necessary elements, such as the mechanical fastening portion, finger grip and adhesives portions, directly in the line of manufacture. The closure tape is typically severed at intervals corresponding to the desired length and adhered at an appropriate location along one portion of the diaper. Uniformity of machine handling properties is essential to high speed application of mechanical fasteners to disposable articles.